The background and description of the invention that follows will be cast primarily in terms of greenhouse operations and conditions because it is there that it is believed to have its primary use. However, it should be realized that the invention may find use in other environments.
In commercial greenhouse operations, it is quite common to start the germination of and grow plants in lightweight, tapered, hollow plastic containers. If the plant is likely to be large at the time it is sold, then a relatively large individual pot is utilized. On the other hand, if the plant is started from seed and likely to be small at the time it is sold, then the germination takes place in a small, tapered cavity formed in a thin-walled, vacuum-formed tray that comprises on the order of 72 such cavities that are usually subdivided, as by partial die cutting along flanges between groups of the cavities, into groups. Such trays are hereafter referred to as "cells."
In a typical greenhouse operation, a plurality of pots or cells are placed on trays that are used to transport the plants throughout their stay in the greenhouse. It is on these trays that the pots are packed with soil, the seeds or plants placed in the pots and the trays then transported to benches for subsequent growing and handling. Heretofore, when arranging the pots or cells on the greenhouse trays, it has been necessary for the individual to remove the pots from the shipping container in which they are received from the supplier and, one at a time, or several at a time, arrange the pots or cells on the greenhouse trays. This is a lengthy operation involving substantial time and attendant high cost.
The pots or cells, as previously indicated, are usually received from a supplier in a shipping container that includes a plurality of layers of nested pots or cells. The pots or cells usually incorporate packing lugs so that they can be more easily removed from the stack.
Applicant has found that by the use of an unloader member having deformable retaining members that are urged into the pots, or some of the individual cavities of a cell, an entire layer of pots or an entire group of cells can be lifted out of the shipping container in a single operation and placed upon a greenhouse tray. It is especially advantageous if the number of pots in a single layer in the shipping carton corresponds to substantially the number of pots that are to be placed on a tray. If this is the case, then an entire tray can be loaded in a single operation.